Nanocrystalline-cellulose-reinforced poly(vinylidenefluoride-co- hexafluoropropylene) nanocomposite films as a separator for lithium ion batteries

Nanocrystalline cellulose (NCC) was synthesized by the facile acid hydrolysis of Kim Wipes tissue papers and characterized with atomic force microscopy (AFM) and X-ray diffraction (XRD). AFM images confirmed the nanosize of the cellulose nanocrystals, and XRD data revealed the high crystallinity. NCC-reinforced poly(vinylidene fluoride-co-hexafluoropropylene) (PH) nanocomposite films were fabricated via an electrospinning method. Different concentrations of NCC in the PH matrix were studied. The effects of the NCC content on the tensile modulus, the variation of tensile modulus with temperature, and the thermal properties of the fabricated nanocomposite films were investigated. It was found that PH + 2 wt % NCC was the optimum composition of the nanocomposite. The addition of 2 wt % NCC in the PH films led to a 75% improvement in the tensile modulus. Dynamic mechanical analysis of the PH nanocomposite films with 2 wt % NCC exhibited high values of tensile modulus in the 30-150°C temperature range. High concentrations of NCC led to decreases in the tensile modulus and thermal properties of the separator. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012